HD64F3687GFP Renesas Electronics America, HD64F3687GFP Datasheet - Page 285

• Manufacturer Part Number: HD64F3687GFP
• Description: IC H8 MCU FLASH 56K 64-LQFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300H Tinyr

Specifications of HD64F3687GFP

• Core Processor: H8/300H
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: I²C, SCI
• Peripherals: LVD, POR, PWM, WDT
• Number Of I /o: 45
• Program Memory Size: 56KB (56K x 8)
• Program Memory Type: FLASH
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

The watchdog timer is an 8-bit timer that can generate an internal reset signal for this LSI if a
system crash prevents the CPU from writing to the timer counter, thus allowing it to overflow.
The block diagram of the watchdog timer is shown in figure 14.1.
14.1
14.2
The watchdog timer has the following registers.
WDT0110A_000020020200
Selectable from nine counter input clocks.
Eight clock sources ( /64, /128, /256, /512, /1024, /2048, /4096, and /8192) or the
internal oscillator can be selected as the timer-counter clock. When the internal oscillator is
selected, it can operate as the watchdog timer in any operating mode.
Reset signal generated on counter overflow
An overflow period of 1 to 256 times the selected clock can be set.
Timer control/status register WD (TCSRWD)
Timer counter WD (TCWD)
Timer mode register WD (TMWD)
Features
Register Descriptions
[Legend]
TCSRWD: Timer control/status register WD
TCWD:
PSS:
TMWD:
oscillator
Internal
Timer counter WD
Prescaler S
Timer mode register WD
Figure 14.1 Block Diagram of Watchdog Timer
Section 14 Watchdog Timer
CLK
PSS
TCSRWD
TCWD
TMWD
Rev.5.00 Nov. 02, 2005 Page 251 of 500
Section 14 Watchdog Timer
Internal reset
signal
REJ09B0027-0500